The present invention relates to a landfill site covering system, particularly to a mobile landfill site covering system.
Much domestic and commercial refuse is disposed of in landfill sites. Such landfill sites commonly attract large numbers of birds. This presents a particular problem near airports, where large numbers of birds increase the risk of hazardous bird strikes during landing or take-off of aircraft. In order to minimise this risk, many national aviation authorities carefully control land usage around airports. For example, in the UK, the Civil Aviation Authority requires complete covering of landfill sites within 8 miles of an airport. Such covering also prevents surface litter from blowing out of the site.
One current method of covering a landfill site involves the erection of large support posts which are anchored in the ground (usually in concrete) in a rectangular configuration, with wires strung between pairs of posts to form a support structure. A net is then spread over the wire support structure and secured to the ground around the posts to form a completely enclosed space. The posts are generally between about 6 to 30 m in length to enable waste lorries to drive onto the site and unload beneath the cover (the netting on one side being partially retractable to allow vehicle entry). When the covered region of the site has been filled with waste and overlaid with soil, the covering can be disassembled and re-erected at a different location on the site. It will be understood that the erection, disassembly and re-erection of such a cover is time consuming and expensive and permits little flexibility in site usage.
A partial solution to this problem is to mount support posts on rollers on a pair of pre-prepared runways. The runways are laid on parallel raised banks having flattened tops. As described above, netting is spread over wires arranged between corresponding posts on each runway. When a particular area between the posts is filled to the required depth, the posts and netting cover can be moved (by using a vehicle to drag the posts along the runway) to cover a different region between the banks. Such a method, although offering some flexibility is still expensive. In addition, the ground must be prepared for the laying of the runways. Several sets of runways may be required.
It is an object of the present invention to provide an improved landfill site covering system which obviates or mitigates one or more of the disadvantages of the known systems.